Fiber Bragg gratings (FBGs) have numerous advantages over traditional foil strain gages, most notably in that they can be embedded in host materials and used to evaluate local deformation. Among the wide variety of grating architectures that have been studied, FBGs inscribed in polarization-maintaining (PM) or other birefringent fibers provide a unique, quantifiable response to strain transverse to the fiber axis. In this work, we show that a PM FBG can accurately predict the asymmetry in transverse strain of a host material in embedded configurations. We do this by diametrically loading an epoxy cylinder that has a uniform PM FBG embedded in the center. We use elasticity and finite element modeling (FEM) to correlate the mechanical response of an embedded fiber with that of the host. An analytical solution of the nominal relationship between Bragg wavelength and strain is included for this loading condition.

中文翻译：

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聚合物包埋，保偏光纤布拉格光栅的横向应变测量

光纤布拉格光栅（FBG）与传统的箔片应变仪相比具有许多优势，最显着的是它们可以嵌入主体材料中并用于评估局部变形。在已研究的各种光栅架构中，刻在偏振保持（PM）或其他双折射光纤中的FBG对横向于光纤轴的应变提供了独特的，可量化的响应。在这项工作中，我们表明PM FBG可以准确地预测嵌入式配置中基质材料的横向应变的不对称性。为此，我们需要沿直径方向装入一个在中心嵌入均匀PM FBG的环氧树脂圆筒。我们使用弹性和有限元建模（FEM）将嵌入式纤维的机械响应与主体的机械响应关联起来。